A great variety of sensors for measuring an acceleration are well known from the state of the art.
Often, a known acceleration sensor for measuring an acceleration, in particular for measuring a vibration, such as acoustic vibrations or acoustic frequencies, typically consists of a housing comprising a measuring plate, especially a piezoelectric or piezoresistive bimorph-plate, which is bonded to a post by a glue, e.g. by an epoxy resin. Preferably, the aforementioned measuring-plate and post combination is coupled with a phenolic shield attached to the inside of the sensor's housing, surrounding the measuring-plate. This measure slows the heat from reaching the measuring-plate and reduces the temperature transient effects slightly, but does not avoid feigning an acceleration which is, in reality, actually not present.
To illustrate the problems with the prior art acceleration sensors, in FIG. 1a and FIG. 1b a prior art sensor is schematically represented which prior art sensor is designated in the following by the reference numeral 1′. Within the framework of the present patent application, all reference numerals related to the features of the prior art sensor 1′ are supplied with a prime in order to distinguish the prior art sensor 1′ clearly from a sensor in accordance with the present invention.
The sensor 1′ according to FIG. 1a comprises a housing 2′ in which housing 2′ a measuring plate 3′ is bonded at a first surface 4′ via a post-bonding-face 61′ to a post 6′. The post 6′ is bonded to the measuring-plate 3′ by a glue, in particular by an epoxy resin. The measuring-plate 3′ is in the present example a bimorph measuring-plate 3′, in particular a piezoelectric and/or a piezoresistive measuring-plate 3′, comprising a first sub-plate 31′ and a second sub-plate 32′, and is polarized by a bending of the measuring-plate 3′, which effect is actually well known to the person skilled in the art. The prior art sensor 1′ according to FIG. 1a is displayed in the operating state. That is, an acceleration A is acting on the sensor 1′ in the direction of the arrow D. Due to the acceleration A acting on the sensor 1′, the measuring-plate 3′ is bent in the opposite direction with respect to the direction D of the acceleration A. Thus, the acceleration meter 9′ reads the acceleration A acting on the sensor 1′.
When there is no bending of the measuring plate 3′ due to temperature effects, the acceleration meter 9′ will display the correct value of the acceleration A acting on the sensor 1′.
In FIG. 1b the sensor 1′ according to FIG. 1a is shown in the non-operating state, that is, no acceleration A is acting on the sensor 1′ of FIG. 1b and the acceleration meter 9′ should read zero.
But due to the temperature T acting on the housing 2′ of the sensor 1′, there is a certain amount of heat that is transferred via the post 6′ to the measuring-plate 3′. A bending of the measuring-plate 3′ occurs as a result of different coefficients of expansion of the post 6′ and the measuring-plate 3′, respectively. That is, a bending of the measuring-plate 3′ occurs due to temperature transient effects. In other words, a temperature-effect A caused by the temperature T is not compensated.
As a result, the acceleration meter 9′ reads an acceleration AT, which is, in reality, actually not present. Thus, there is a bias voltage drift with temperature transients and, therefore the acceleration meter 9′ does not display the correct acceleration A acting on the sensor 1′, which acceleration is, in reality, zero in the example of FIG. 1b. 
Thus, the known prior art sensor 1′ does not provide exact acceleration measurement data in case that the sensor 1′ is exposed to any temperature effect, e.g. to temperature changes in its environment.